I have one of my VM's backup that failed to sync accross replication.
Backup01 is my main PBS. Backup02 & 03 sync every night on Backup01.
On 02 & 03, I have the following error logged :
2025-08-25T10:30:21+02:00: sync group vm/131 failed - while creating locked snapshot 'BackupDir { store: "datastore", ns: BackupNamespace { inner: [], len: 0 }, dir: BackupDir { group: BackupGroup { ty: Vm, id: "131" }, time: 1756062460 }, backup_time_string: "2025-08-24T19:07:40Z" }': unable to acquire snapshot lock "/run/proxmox-backup/locks/datastore/vm-131-2025\\x2d08\\x2d24T19\\x3a07\\x3a40Z": Unable to acquire lock "/run/proxmox-backup/locks/datastore/vm-131-2025\\x2d08\\x2d24T19\\x3a07\\x3a40Z" - Resource temporarily unavailable (os error 11)
2025-08-25T10:30:21+02:00: skipped: 23 snapshot(s) (2024-07-28T19:00:02Z .. 2025-08-23T19:00:00Z) - older than the newest snapshot present on sync target
2025-08-25T10:30:21+02:00: re-sync snapshot vm/132/2025-08-24T19:00:06Z
2025-08-25T10:30:21+02:00: no data changes
PBS try to lock the backup in order to sync it. It says it want to acquire a lock file located in "/run".
The file exists on source server :
ls /run/proxmox-backup/locks/datastore | grep vm-131
-rw-rw---- 1 backup backup 0 Aug 25 10:30 'vm-131-2025\x2d08\x2d24T19\x3a07\x3a40Z'
lslocks does not report any active lock on any of the files :
COMMAND PID TYPE SIZE MODE M START END PATH
multipathd 548 POSIX 3B WRITE 0 0 0 /run/multipathd.pid
zed 1146 POSIX 5B WRITE 0 0 0 /run/zed.pid
zed 1146 POSIX WRITE 0 0 0 /run/zed.state
master 1434 FLOCK 33B WRITE 0 0 0 /var/spool/postfix/pid/master.pid
master 1434 FLOCK 33B WRITE 0 0 0 /var/lib/postfix/master.lock
tlsmgr 1607 FLOCK 8K WRITE 0 0 0 /var/lib/postfix/smtp_scache.db
I have also rebooter the whole backup server to be sure...
What can be wrong with this particular lock file, explaining this problem ?
Any way to diagnose the root cause which does not seems to be the lock file itself ?
Backup01 is my main PBS. Backup02 & 03 sync every night on Backup01.
On 02 & 03, I have the following error logged :
2025-08-25T10:30:21+02:00: sync group vm/131 failed - while creating locked snapshot 'BackupDir { store: "datastore", ns: BackupNamespace { inner: [], len: 0 }, dir: BackupDir { group: BackupGroup { ty: Vm, id: "131" }, time: 1756062460 }, backup_time_string: "2025-08-24T19:07:40Z" }': unable to acquire snapshot lock "/run/proxmox-backup/locks/datastore/vm-131-2025\\x2d08\\x2d24T19\\x3a07\\x3a40Z": Unable to acquire lock "/run/proxmox-backup/locks/datastore/vm-131-2025\\x2d08\\x2d24T19\\x3a07\\x3a40Z" - Resource temporarily unavailable (os error 11)
2025-08-25T10:30:21+02:00: skipped: 23 snapshot(s) (2024-07-28T19:00:02Z .. 2025-08-23T19:00:00Z) - older than the newest snapshot present on sync target
2025-08-25T10:30:21+02:00: re-sync snapshot vm/132/2025-08-24T19:00:06Z
2025-08-25T10:30:21+02:00: no data changes
PBS try to lock the backup in order to sync it. It says it want to acquire a lock file located in "/run".
The file exists on source server :
ls /run/proxmox-backup/locks/datastore | grep vm-131
-rw-rw---- 1 backup backup 0 Aug 25 10:30 'vm-131-2025\x2d08\x2d24T19\x3a07\x3a40Z'
lslocks does not report any active lock on any of the files :
COMMAND PID TYPE SIZE MODE M START END PATH
multipathd 548 POSIX 3B WRITE 0 0 0 /run/multipathd.pid
zed 1146 POSIX 5B WRITE 0 0 0 /run/zed.pid
zed 1146 POSIX WRITE 0 0 0 /run/zed.state
master 1434 FLOCK 33B WRITE 0 0 0 /var/spool/postfix/pid/master.pid
master 1434 FLOCK 33B WRITE 0 0 0 /var/lib/postfix/master.lock
tlsmgr 1607 FLOCK 8K WRITE 0 0 0 /var/lib/postfix/smtp_scache.db
I have also rebooter the whole backup server to be sure...
What can be wrong with this particular lock file, explaining this problem ?
Any way to diagnose the root cause which does not seems to be the lock file itself ?
